Multifunctional ZnO/Fe-O and graphene oxide nanocomposites: Enhancement of optical and magnetic properties

Abstract

ZnO is a semiconductor with a great interest, but it has several deficiencies which limit its use in technologic applications. One important limitation is having the band gap in the UV which reduces its use in optical devices. To solve this problem, in this work, composites based in ZnO with goethite and graphene oxide (GO) by sol-gel are prepared. The obtained samples (powders and thin films) were characterized microstructurally (DTA, XRD, micro-Raman, FE-SEM), optically (transmittance and photoluminescence) and magnetically (SQUID). The ZnO band gap of multifunctional composites shows a red-shift towards visible range (E ∼3.01 eV) with high transmittance ∼85% (thickness of 362 nm) over the visible wavelength range. A long-range magnetic order at room temperature appears in these nanocomposites (Ms = 1.60·10 emu/g). The combination of both dopants allows modifying the functional properties of ZnO, opening a great field of applications in ZnO composites, such as spintronic and optoelectronic devices.